| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 | 
                                    
                                    0.2%
                                 | 
| -7 | Does not apply (sponatneous) | 25 | 
                                    
                                    2.4%
                                 | 
| 1 | Yes | 251 | 
                                    
                                    24.5%
                                 | 
| 2 | No | 746 | 
                                    
                                    72.9%
                                 |